public object Argument { get; }

Public ReadOnly Property Argument As Object

private void StackedBarChart_CustomizeStackedBarTotalLabel(object sender, CustomizeStackedBarTotalLabelEventArgs e) {
    if (e.Argument.ToString() == "A" || e.Argument.ToString() == "D") {
        e.Text = String.Empty;
    }
}

Private Sub StackedBarChart_CustomizeStackedBarTotalLabel(ByVal sender As Object, ByVal e As CustomizeStackedBarTotalLabelEventArgs)
    If e.Argument.ToString() = "A" OrElse e.Argument.ToString() = "D" Then
        e.Text = String.Empty
    End If
End Sub